Motor-meter.



No. 698,664. Patented Apr. 29, I902.

I T. DUNCAN. I MOTOR METER. [Applicmion filed Oct. 11, 1899 Renewed Jan.6, 1902.)

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Patenfed Apr. 29, I902 T. DUNCAN.

I MOTOR METER. (Application filed Oct. 11, 1899. Renewed Jan. 6, 1962) 2Sheets-:Sheet 2.

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THOMAS DUNCAN, OF CHICAGO, ILLINOIS, ASSIGNOR TOTHE SIEMENS &

IIALSKE ELECTRIC COMPANY OF AMERICA,

CORPORATION OF ILLINOIS.

OF CHICAGO, ILLINOIS, A

VMOTOR-SMEYTER.

SPECIFICATION forming part of Letters Patent No. 698,664, dated April29, 1902. Application filed October 11, 1899. Renewed January 6, 1902.Serial No. 88,485. m0 modem To all whom it may concerni Be it known thatI, THOMAS DUNCAN, a citizen of the United States, residing at Chicago,in the county of Cook and State of Illinois, have invented a certain newand useful Improvement in Motor-Meters, (Case No. 286,) of which thefollowing is a full, clear, concise,

and exact description, reference being had to three-phase system ofdistribution that mag netic fields can be obtained in the meter torepresent the impressed electromotive force of the work-circuits orthose circuits whose current traverses the series field-windings and tomaintain these magnetic fields in quadrature with the impressedelectromotive force of the pressure-circuits in a manner similarto thepractice employed in single or two phase induction motor-meters.

It is well known that in order to measure accurately inductive loads themagnetism representing the pressure must be displaced ninety degreesfrom the pressurethat is, it must either lag or lead the phase of thepressure by ninety degrees. I am aware that an arrangement has been usedfor measuring three-phase currentsin employing two motors attached to asingle spindle and registering devico; but the practice is to treat eachin the same manner as a single-phase meter-that is, by supplementing theshunt or pressure field-windings of themeter with an auxiliary coilwhichis the seat of induced currents and is short-circuited upon itselfthrougha suitable and generally an adjustable resistance. In the presentarrangement I employ only the three circuits or pressures without anyaux-' iliarysecondaries' or other subsidiary phasechanging devices.

My'invention will be more readily understood by reference to theaccompanying draw- Figure 1 is a diagrammatic view of adoublemotorarrangement embodying my invention and one in which the arrangementshown would accurately measureall power factors,

whether the several power-circuits are bal anced or not. Fig. 2 isa-diagrammatic view showing the use of a single-motor arrangement whichis applicable only to cases where the threecircuitsareperfectlybalanced,which is acondition that rarely exists in'practice.

Fig. 3 is also a diagrammatic View whereinnected in circuit, asshown-that is, each series coil is connected in one of the main leads ofthe system which comprises the threeph'ase generator a and the motor I),connected by the three leads 0 d e. The series field- 'windings may beconnected to any two of the three leads. I have shown themin Figs. 1 and3 a's-connected to the upper and lower. In inductive relation to theseries field-windings are two aluminium inverted-cup-shaped armaturesmechanically connected and preferably mounted upon the same spindle, andeach armature is also in inductive relation to two pressure field-windings, as hereinafter explained.

The apparatus illustrated in Fig. 2 has the same mode of operationsubstantially as that of Fig. 1, and as it is less complicated, owing toits having only one motor device, I will explain my invention in detailby reference to this figure. I

The three-phase generator is shown as supplying current to an inductiveload 1); but it will be understood, of course, that lamps or othertranslating devices may be connected in circuit'it' desired, since themeter will measure the true energy of the circuit in watts'irrespectiveof the load conditions.

In one of the leads 0 I include the series field-coil f, through whichpasses thecnrrent over the wire a. 'In inductive relation to thisfield-coil and suitably mounted to revolve is the aluminium armature72.. To cause a magnetic field that will represent the pressure inVolts, I em ploya shunt-windingp, that is supplied from an artificialneutral resistance -m. resistance is to reproduce the pressureconditions of the three coils of. the dynamo, which is necessary only inthe case of starwound generators and systems of distribution, as is.shown in Figs.v1, 2, and 3 herein,

because with mesh systems of winding the pressure of the circuits is thepressure of the skilled in the art. The series field-winding f beingconnected directly in the circuit 0, the current therethrough will be inphase with the pressure of the corresponding gen erator-coil, assumingthat the load is a noninductive one. This current and pressure may beassumed to be represented by the line 70, Fig. 4, while the remaininglines land m represent the other two currents and pres, sures of thesystem. r 1

' It is necessary for the operation of themeter to get a voltagemagnetic field that is displaced ninety degreesfrom Ya. In order tosecure this result, the shunt-winding p is connected to the terminals ofthe resistancelby means of the wires 1 'n 2, and its phase relation to713 is shown by Z in Fig. t. Then the other coil 0 is connected to theterminals of the resistance m bythe wires 3 n at. The connections of thecoil 0 are-such that its phase relations lie between the lines 7c and l,and the current and pressure of this coil, therefore, are represented bythe line m of Fig. 5. By combining the two currents or magnetisms of thewindings 0 and p, which are represented by the lines Z and m of Fig. 5,the resultant t of Fig. 6 is obtained, which is at right angles to orninety degrees from the line 7a, which represents the impressedelectromotive force of the circuit. 7

Where two motors are employed, the series field-windings are connectedin the leads 0 and e, and in this case the shunt field-winding 1' willbe supplied from k of the artificial neutral resistance and have Zreversed through q, as shown in Fig. 7, thereby making the line m andthe resultant i ninety degrees apart.

In the diagram of Fig. 8 there is shown the effect of the presence ofinduction in the shunt field-windings o and p, which brings theresultant t beyond ninety degrees; but

this variation can be compensated for in any Well-known manner, such asis shown in Fig. 3, by the use of adjustable resistances :1: and Thediagram of Fig. 9 shows the resultant t corrected to quadrature with 7cby increasing the magnitude of C. In these Figs. 8 and 9 The function ofthis artificial neutral C andB represent the lagging magnetism producedby the current obtainedfrom the resistancesm and I, also representingthe electromotive forces. By varying the adjustable resistances theeffect of the current through the coils may be varied so as to securethe resultant 25' at right angles to 70, as is shown.

' It is not essential that two artificial neutral resistances should beemployed, as is shown in Fig. 1. I have shown in Fig. 3 the employmentol'a single artificial neutral resistance supplying both motors of themeter. Each of the two artificial neutral resistances of Fig.

1 reproduces the pressure relations of the generator, and one thereforemay be used for both motor devices just as well as to duplicate them.

The essential features of my invention will be understood by referenceto the Figs. 4, 5, and 6, 7, 8, and 9. I have explained by thesediagrams how I make use of the reproduction of the pressure relationsofthe generator, which results from the use of' the artificial neutralresistance to prod uce a resultant magnetic field for thepressure-winding which shall be maintained in quadrature with theimpressed electromotive force of the circuit including the seriesfield-winding. This result having been secured, the method of indicatingor integrating the true watts flowing in the circuit will be readilyunderstood by those skilled in the art. The total turning effect uponthe movable element of the meter exercised by the magnetic fields bywhich the arm atu res are influenced will be proportional to the trueenergy of the circuit, and this may be integrated by the well-knownmeans of a counting-train attached to the armature and which I haveindicated in Fig. 1. The inechanical connection between the twoarmatures, which is preferably secured by mounting them upon onespindle, is indicated by dotted lines connecting the armatures in Fig.1.

The portions 0 p constitute inductively-related coilsof the meterpressure-winding.

Various modifications in the details of the apparatus and circuits bywhich my invention may be realized will occur to those skilled in theart. I do not wish, therefore, to be limited to the specific apparatusand arrangement of circuits shown; but,

Having described my; invention, what I claim as new, and desire tosecure by Letters Patent, is-

2. In a motor-meter the combination with current and pressurewindings-for effecting 1 I of the working circuit, and an armature 1nthe movement of the movable element of the meter, of an artificialneutral resistance adapted for interposition between the mains of thecircuit independently of said pressure winding, and in cooperation withsaid pres sure-winding serving to'maintain'the desired phase relationbetween the pressure field and the electromotiv'e force of the workingcir; cuit, substantially as described.

3.-- The combination with a three-'phas'e'sjvsf tem ofalternating-current distribution, of a motormeter having current andpressure windings, and an artificial neutral resistance connecteddirectly between the sidesot' the system independentlyof thepressure-winding and cooperating with thepressure-winding to maintainthe desired phase relation between the pressure-field and theelectrometive 'force of the working circuit, substantially as described.

4. The combination with a three'phase systemof alternating-currentdistribution, of a motor-meter having current and pressure windings, andan artificial neutral resistancehaving three branches interposed betweenthe sides of the three branches of the system independently of thepressure-winding and cooperating with the pressurewinding to maintainthe desired phase relation between the pressure-field and theelectromotive force of the working circuit, substantially as described.

5. In a motor-meter, the combination with current and pressure windingsfor efiecting the movement of the movable element of the -meter, of anartificial neutral resistance adapted for interposition between themains of the circuit independently of said pressure. --winding,, and incooperation'with said pressure-winding serving to maintain the desiredphase relation between the pressure-field and the'electromotive force ofthe working cireuit, and an armature in inductive relation with saidpressure and current windings, substantially as described. V

6. The combination with a three-phase system of alternating-currentdistribution, of a motor-meter having current and pressure windings, andan artificial neutral resistance connected directly. between the sidesof the system independentlyof the pressure-winding and cooperating withthe pressure-winding to maintain the desired phase relation between thepressure-field and the electromotive force of the working circuit, andan armature in inductive relation with said pressure and currentwindings, substantially as described.

7. The combination with a three-phase system of alternating-currentdistribution, of a motor-meter having current and pressure windings, andan artificial neutral resistance having, three branches interposedbetween the sides of the three branches of the system independentlyrofthe pressure-winding, and cooperating with the pressure -winding to jmaintain the desired phase relation-between the pressurefieldan'dtheelectromo'tive force inductive relation with said pressureand current windings, substantially as described.

8'. -In a'motor-metelythe comb'inationwith current and pressure windingst'or'effecting the movement of the movable element of the meter,ot'an'artificial ne'u tral resistance adapted for interposition betweenthemains of the circuit independently ofsaid pressure-wind ing, and incooperation with-said pressure: windingserving to maintainthe'd esired'phase' relation between the I pressure-field an'd theelectromotive' force"ot'--the' working: circuit,

' said pressure-winding 'receiving' its current through said resistance,substantially as described. 4

9. The combination with a three-phase system of alternating-currentdistribution,of ax motor-meter having current and pressure windings, andan artificial neutral resistance connected directly between the sides of"the system independently of the pressure-winding and cooperating withthe pressure-winding to maintain-the desired; phase relation between thepressure-fieldand the electromotive force of the working circuit, saidpressure-winding receiving its current through said resistance,substantially as described.

10. The combination with a three-phase system of alternating-currentdistribution, of a motor-meter having current and pressure windings, andan artificial neutral resistance having three branches interposedbetween lated coils, of a star-connected resistance re ceiving currentindependently of the 'pres-.

sure-winding, each 'coil of which is connected across a branch of thestar-connected resistance, substantially as described.

12. In a three-phase meter, the combination with a movable element,'of acurrent fieldwinding in inductive relation therewith, a pressure-coilalso in inductive relation therewith, a secondpressure-coil also ininductive relation with said movable element and adapt ed to haveitsphase relation lie between the impressed electromotive force ofthecircuit including the current-winding and that of the current in saidfirst pressure-coil, and a starconnected artificial resistance receivingcurrent from the work-circuitindependently of the pressu re-winding,eachpressure-coil beingv connected across abranchof the said artife cialresistance, substantially as described.

13. In a three-phase meter, the combination I with current and pressurewindings, the latter being divided into two coils, of a starconnectedresistance receiving current independently of the pressure-winding, eachcoil of which is connected across abranch of the starconnectedresistance, substantially as described.

14. In amotor-ineter, thecombination with current and pressure windings,the pressurewinding being divided into two inductivelyrelatedcoilsincluded in circuit with each other, of phase-modifying resistancehaving branches in parallel with said pressu re-coils,

- substantially as described,

15.- In a three-phase meter, the combination with current and pressurewindings, the latter being divided into two inductively -relatcd coils,of a star-connected resistance re- THOMAS DUNCAN.

Witnesses:

GEORGE L. CRAGG, CHARLES E. HUBERT.

